The present invention relates to a device for ventilating a vehicle seat. The present invention further relates to a use of such a ventilation device.
Seat ventilation devices are generally known from the prior art; whereas, for example, in the field of higher-value motor vehicles generically known devices for supplying air to users which are in contact with a seat and/or back contact face in the operating state of a vehicle seat and which are acted on with air which is drawn in by the ventilator unit—generally from the vehicle interior—and which is discharged through the seat or back contact face, are becoming increasingly popular. The use of a seat ventilation device of the type described so as to increase comfort and safety, for instance, has been carried out and found to be advantageous for a long time in aircraft, construction, agricultural or military vehicles, and particularly in operating environments which are particularly demanding.
Conventionally, for the purpose of air supply to the seat or back contact face, a cushion which is generally produced from a suitably resilient foam material for the seating purposes of the user is provided with a through-channel as an air flow channel in such a manner that the ventilator unit which is generally received in a ventilator housing in a modular manner draws in the incoming air through this channel and then discharges it at the outlet side to the seat or back contact face, wherein this outlet is often provided with a covering unit which is rigid and air-permeable in a manner known from the prior art. That covering unit primarily has the purpose of preventing inadvertent sinking of a user in the event of point-like weight loading of the cushion—the so-called “knee test”—wherein, to this end, the covering unit which is typically constructed in a grid-like manner brings about a substantially planar and fixed covering of the ventilator outlet at the end of the user-side end of the air flow channel.
In devices which must be presumed to be known from the prior art, this covering unit is typically constructed as a closure or end-side delimitation of the ventilator housing, wherein, in particular from the point of view of large-batch production and in order to implement the described modular notion, those subassemblies can then be integrated, often also integrally, by suitable plastics injection-molding technologies in order thus to allow a cost-effective capacity for production with easy assembly properties, that is to say, by simple introduction into the flow channel in the cushion.
A layer (which is flat and narrow relative to the cushion) comprising a material which is air-permeable and therefore which conducts air along or parallel with the seat or back contact face is then often further applied to the seat or back contact face of the (foam) cushion with the objective of ensuring a discharge of air which is distributed over a surface-area to the greatest possible extent and which is adapted to the anatomical user conditions of the seated user for a covering layer which is then tensioned thereon (for example, a leather seat cover which is suitably perforated for the discharge of air).
While particularly in the case of detrimental ambient temperatures in the vehicle such seat ventilation technologies can significantly increase the driving comfort of the user and therefore a passive operating reliability of the vehicle which is equipped in this manner; nevertheless, the technology which is presumed to be known in a generic manner and in accordance with the preamble of claim 1 has been found to be in need of improvement, with particular regard to the particular ventilation and fitting conditions of a vehicle seat: an axial ventilator which is usually introduced in the context of the generic ventilator unit as a ventilator motor is dimensioned, together with the additional components of the air flow chain, so that a conveying volume can be achieved in the range between approximately 4 liters/sec. and approximately 10 liters/sec., wherein typical seat contact faces of motor vehicles have a plurality of air flow channels (which are spaced apart from each other and separated in terms of flow) together with the respective ventilator units and covering units. With respect to the dimensions of the ventilator, including an achievable diameter of the ventilator rotor, the radial construction space is initially limited, for example, by the problems described in the introduction in that non-homogeneities in the (foam) cushion have a negative effect on the support properties of the cushion and the seating comfort, wherein, for example, an excessively large diameter of the described covering unit (since it is itself rigid) could also potentially be detrimental to comfort. In addition, there is the problem that the plurality of mutually adjacent air flow channels generally intended to be provided in the same cushion have to have a sufficient minimum spacing from each other in order to ensure a stable retention or securing action of the ventilator units on or in the cushion.
In order, in view of these geometric limitations of the installation conditions in the vehicle seat and the (radial) ventilator diameter which is thereby limited, nevertheless to ensure a high air transport volume, it is conventional to produce ventilator units which are used for ventilating seats at high ventilator speeds of the ventilator rotor; these may be up to 10,000 rpm.
However, it has been found to be disadvantageous in the context of the invention that there occur, during operation of a ventilator rotor at such high rotation speeds, vibrations which are transmitted to the user via the rigid covering unit and which can impair the seating comfort in a significant manner. This is why it has thus been found that speeds in the range mentioned can produce an oscillation excitation of the system comprising the covering unit and the ventilator housing, with the disadvantageous effect that resonance frequencies which have just been excited may in this instance lead to considerable vibration effects and the described losses of comfort. In addition, there is potentially disruptive noise generated and the potential risk of mechanical impairments of the ventilator motor which drives the ventilator rotor together with bearings in such resonance situations.